It is possible to associate Amazon Web Service instances with some different forms of IP addresses: private, elastic or public. There are generally two Internet Protocol versions: version 4 and 6. AWS IPv6 and IPv4 addresses can be of the private and public types. Amazon Web Services does not yet support the elastic addresses for Internet Protocol version 6. Read on to know more regarding these three forms of Internet Protocol addresses that AWS provides.
Public IP Address
Communication beyond the network happens through this IP address. It is useable to communicate between virtual machines in AWS and the internet. The best potential use scenario for these is as part of small projects in which dynamic IP is useable without much overhead. Amazon Web Services has more than one million public-type IP addresses, plus it continues to add fresh ones.
These are similar to the elastic addresses in that both are public and enable communication between AWS instances and the internet. Anyhow, the addresses differ in how these are connected to AWS’s EC2 instances.
The addresses are allotted to the instances through Amazon’s public IPv4 address pool when these machines are started. The addresses stay allotted to each AWS virtual machine up to the time the VM is stopped. In the event of the machine being stopped and then started later, a fresh IP address would be allotted to it.
Private IP Address
It is utilized to communicate within your local network, so it cannot be reached through the internet as in the case of the public address. It is useable to communicate from one virtual machine in AWS’s VPC environment to another instance. It stays associated with AWS’s instance at the time of the machine being stopped or restarted. It would only dissociate from the instance if that VM is terminated.
An AWS virtual machine being launched enables you to allot the address to it. If you do not perform the above, EC2 would assign it to the machine within the range of addresses in the VPC. When you do not stipulate a private IP address from Amazon Web Services, it would choose one that is available in that range. It is also possible to allot a secondary IP address.
Elastic IP Address
It is a static IP address made to facilitate dynamic cloud computing. It is allotted to one’s Amazon Web Services account instead of a specific virtual machine. Associating it with your AWS instance will keep it allotted to the account and this virtual machine until its dissociation from either happens.
Helping with AWS’s fault-tolerant virtual machines or software, is the most common use of this IP address. For instance, in the event of your EC2 instance with the address becoming stopped/terminated, you could remap and reconnect it to a different VM in your AWS account. You could also reconnect the same address to that instance after it is rebooted.
